Bobbins



Dec. `29, 1959 u w. M. cAMP 2,918,888

BOBBINS Filed April 24, 1956 y T uz'll. T Lc- INVENTOR M//LL/AM M. CAMP ATTORNEYS United States Patent O BOBBINS William M. Camp, Glen Ridge, NJ., assignor to Coats &

Clark Inc., New York, N.Y., a corporation of Delaware The present invention has to do with sewing machine bobbins and the manufacture thereof. It relates particularly to a bobbin which comprises a central tube and two parallel side walls attached to said tube. Such bobbins may be made of metal, plastic or paper.

The present invention contemplates the use of the last mentioned material because it is cheap and readily worked to accommodate itsel-f to the method described.

The type of bobbin which is herein described is usually purchased with the thread mass wound thereon and after the removal of the thread the bobbin itself is discarded. Of necessity such bobbins must be very low priced. This type of bobbin is commonly used by manufacturers of garments and the like where it is undesirable to rewind a bobbin because of the time spent in so doing. It is desirable with commercial high speed machines to have a bobbin made of light weight material so that when the thread is drawn oif the bobbin very rapidly the bobbin does not overrun and cause the thread to tangle in the bobbin case. walls of the bobbin tit snugly against the thread mass so as to avoid having the thread jam between the thread mass and inside of the side walls. It is also desirable to have a bobbin which when wound with thread maintains its original dimensions and `does not expand or change its dimensions as time elapses. All of these desired results and advantages are obtained with the present invention as will be more fully described hereinafter.

The following is a description of my invention, reference being had to the accompanying drawings in which Fig. 1 is a perspective view of a short piece Vof tube with a thread mass wound thereon and a pair of wall blanks for the bobbin walls;

Fig. 2 is a longitudinal central section through the elements shown in Fig.f1;

Fig. 3 is a longitudinal section of a pair of dies, a supporting spindle and the various elements which go to make up the loaded bobbin;

Fig. 4 is a sectional view like Fig. 3 but taken after the dies have been brought together tol assemble the various elements of the bobbin;

Fig. 5 is a section through 5 5 of Fig. 6 showing the engagement of the bobbin walls with the central tube;

Fig. 6 is a perspective view of the finishedV bobbin;

Fig. 7 is a section through 7--7 of Fig. 6.

Looking at Figs. 1 and 2, T shows a thread mass woun on a hollow tube 1. 2 and 3 designate blanks for the walls of the nished bobbin. It will be noted that the tube 1 on which the thread mass T is wound is somewhat longer than the thickness of the thread mass. This permits the wall blanks to be placed over the ends of It is also desirable to have ythe sidev 2,918,886 Patented Dec. 29, 1959 ICC 2 the tube and the tube and wall blanks locked together, as will be hereinafter described.

In assembling the walls on the tube, shaping the same and compressing the thread mass, a pair of dies, such as those shown in Figs. 3, 4 and 5, are used. The upper die member is shown at 5, the lower die member at l6. The face of dies 5 and `6 are furnished with radially disposed corrugations; those on die 5 are shown at 7 and those on die 6 at 8. Each die is also furnished with a central bushing, the surface of which is specifically designed to lock the walls of the bobbin and the tube together. The bushing for die member 5 is shown at 9 and the bushing for die member 6 at 10. A central spindle 11 is designed to pass freely but snugly through the central bore of the bobbin blank and the bushings 9 and 10 of the dies. This spindle centers the blank and prevents collapse of the tube 1 during compressing of the bobbin blank.

In the operation ofthe die mechanism, the members shown in Figs. l and 2, that is, the tube 1 with the thread mass thereon and the tube wall blanks are assembled on the spindle 11, as shown in Fig. 3. The dies are then moved towards each other to the position shown in Fig. 4. During this operation the tube 1 is compressed longitudinally and wrinkled, as shown in Figs. 4 and 5, the ends of the tube are turned over and locked into engagement with the walls of the bobbin, as shown in those igures. Looking at Fig. 5,` the ends of the tube 1 are folded over substantially 90 to form the annular flap 15 which lies over the wall 2. Underneath the wall 2' a wrinkle or bulge is formed in the tube, as shown at 16. This, of course, is produced by the longitudinal compression of the tube and the wall 2 is locked between elements 15 and 16 of tube 1. During this compression operation the thread mass is compressed and radial corrugations are formed on the walls of the bobbin. This result can be best seen in Figs. 6 and 7. One of those corrugations is shown at 17. It will be noted that because the walls are relatively thin, the corrugations are formed both on the outside of the walls and on the inside, as shown in Fig. 7. The spindle 11 is moved upwardly into die 5 to permit removal of the bobbin.

It is desirable to heat thedie members because they will moreA readily shape the elements of the bobbin and the latter will hold its dimensions and shape better if compressed under heat. The dies may be heated by electric resistance elements or by circulating heated liquid therethrough. These features are not shown because their structure is no part of this invention.y

A temperature of about 250 F. has been found advantageous with a paper bobbin and any conventional sewing thread Wound on it.

A bobbin made in accordance with the method herein disclosed has a number of advantages, it is economical because it may be made of paper, it is so constructed that it is relatively strong with the walls firmly locked to the tube, it carries maximum length of thread because the thread mass is compressed, it is economical to make because the assembly of the bobbin and the `compression of the thread mass and the formation of the corrugations on the walls of the bobbin are all performed in one' operation. The corrugated side walls of the bobbin are advantageous because they prevent sticking of the bobbin in the bobbin holder, they permit the bobbin to rotate more. freely and smoothly in the unwinding of the thread which is an important feature in high speed machines` Corrugations on the inside of the walls assist in keeping the thread from falling off the side of the Walls and becoming entangled between the bobbin and bobbin holder.

Although but a specific embodiment of the invention is herein shown and described, it will be understood that numerous detaiis of the construction shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

I claim:

1. In a sewing machine bobbin of the class described, a central tube of paper, a thread mass wound on said tube, annular parallel side walls of paper spaced apart and attached to the ends of said tube, raised radial ribs forming corrugations on the inner surfaces of each of said side walls and conforming corrugations on the side surfaces of said thread mass closely intertting with the corrugations on the inner surfaces of said side Walls.

2. The sewing machine bobbin of claim 1 in which the corrugations on the side surfaces of the thread mass 2,918,386A n K 4 extend from the central tube to the outer periphery of the side surfaces.

References Cited in the le of this patent UNITED STATES PATENTS 1,319,381 Ehnborn Oct. 21, 1919 1,657,755 Janssen Ian. 31, 1928 1,961,730 Baker June 5, 1934 2,098,219 Baker Nov. 9, 1937 2,200,721 Marinsky et al. May 14, 1940 2,203,286 Simpson June 4, 1940 2,331,954 Atwood Oct. 19, 1943 2,340,574 Ashworth Feb. 1, 1944 2,475,399 Nelson July 5, 1949 2,488,890 Anderson Nov. 22, 1949 2,674,215 Thompson et al Apr. 6, 1954 2,678,012 Ayres May 11, 1954 

